Data Scientist Interview Questions
Practice 2,964 real Data Scientist interview questions for 2026. Data Scientist interview questions drawn from Meta, Capital One, Amazon, Google, TikTok and similar employers — real questions from actual interviews with detailed solutions — designed to accelerate your interview preparation for product analytics, ML and production data roles. This collection emphasizes the practical skills interviewers test: SQL and data manipulation, experiment design and A/B testing, statistical reasoning, Python coding for data problems, model evaluation and feature engineering, plus machine-learning system tradeoffs and metric design. What’s distinctive about modern data-science loops is the blend of product thinking and reproducible ML: expect hands-on SQL tasks and funnel analysis in screens, deeper experiment-design and causality questions in mid rounds, and coding or modeling challenges plus ML-system discussions in senior loops. Interviewers evaluate problem framing, statistical rigor, and how you communicate decisions to product partners. To prepare, prioritize daily SQL practice (CTEs, window functions), refresh hypothesis-testing and power calculations, rehearse concise metric-driven narratives, and build a few end-to-end model or experiment stories you can explain clearly under time pressure.

"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"

"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"

"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."

"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."

"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."

"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."

"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."

"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."

"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."

"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."

"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."

"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."

"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."

"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Present a DS project with business impact
7-Minute Data Science Project Presentation (Onsite) Context You are interviewing for a Data Scientist role and will present a past project to a mixed ...
Implement TF–IDF with sparse matrices
Implement TF–IDF from Scratch (Python + NumPy/SciPy) You are given a list of documents (plain strings). Implement a TF–IDF vectorizer from scratch — n...
Find and fix metric drops systematically
Investigating a YoY Drop in Weekly Average Likes per User Context You are a Data Scientist evaluating a social app where the weekly average likes per ...
Explain your most impactful project trade-offs
Behavioral Prompt: 2–3 Minute Project Walkthrough (Data Scientist, Technical Screen) Deliver a concise, 2–3 minute walkthrough of the single most impa...
Achieve 0.95 precision via thresholding
Deploying a High-Precision Classifier on an Imbalanced Dataset You are given a binary classification problem with 50,000 samples and ~5% positives. Th...
Build a leak-free sklearn pipeline
Take-home: Imbalanced Binary Classification Pipeline with scikit-learn You are training a binary classifier on tabular data with the following feature...
Design fraud detection across channels with unknowns
Fraud Detection Strategy for a Multi‑Channel Marketplace Context: You are designing a fraud detection system for a large marketplace operating across ...
Optimize thresholds under fraud costs
Cost-sensitive Thresholding for Fraud (ATO) Classifier Context You are evaluating a binary classifier for account takeover (ATO) fraud on a large vali...
Design an A/B for ATO rule
Experiment Design Case: Real-time ATO Rule for PayPal/Venmo Context: You are designing and analyzing an online experiment to estimate the net business...
Write SQL to backtest refund policy
Using the schema and samples below, write a single SQL query (CTEs allowed) that does all of the following for the last 30 days relative to today = 20...
Calculate power and test duration
A/B Test Sizing: Reducing Cold-Food Complaint Rate You are running an A/B test of thermal delivery bags aiming to reduce the cold-food complaint rate....
Lead cross-functional decision without RCT evidence
Behavioral: Ship vs. Rollback After a Global Launch Without a Holdout Context You are a Data Scientist in a consumer marketplace. An important feature...
Design ad revenue A/B with guardrails
Mobile App Ads Marketplace: Experiment Plan to Lift Revenue by 10% in 60 Days Context You run a mobile app ads marketplace. Target is to increase ad r...
Design experiment for homepage tab replacement
Experiment Design: Replacing a Homepage Tab and Measuring User + Ecosystem Impact Assume today is 2025-09-01. Roblox plans to replace an existing home...
Design real-time live-stream recommendations
Design a Real-Time Recommendation System for Live Streams Context: You are designing a recommender for a large live-streaming platform. Assume you hav...
Decide whether to sell both products
Decision Rule: Offer Classic and Vegan Burgers Concurrently? Context You are evaluating whether a burger chain should sell a vegan burger alongside th...
Challenge and validate assumptions
Vegan-Burger Launch: Assumptions at Risk, Validation, Sensitivity, and Experiment Plan Background You are evaluating the launch of a vegan burger acro...
Compute posterior and event counts in fraud screen
Fake-Account Screening with Threshold on 5 Signals You are designing a rule-based screener that flags an account if at least k of 5 binary signals fir...
Design and analyze batching algorithm experiment
Experiment Design: New Order-Batching/Dispatch Algorithm (Aug–Sep 2025) You are tasked with designing and analyzing a geo-experiment for a new order-b...
Compute average unique pins per user
Task: Average Unique Pins Per User You are given a mapping from user IDs to their lists of pin IDs. Implement a function that computes the mean number...